The applicant's proposed research is an exploration of the barriers that influence adherence to antiretroviral therapy (ART) by HIV-positive individuals who use illicit drugs. Twenty years of research suggest that patient characteristics, provider factors, treatment regimen factors, and social/environmental factors play a role in chronic disease treatment compliance. However, few studies have explicitly linked these factors to non-adherence among HIV-positive individuals who use illicit drugs. The proposed study aims to study the impact of these potential barriers through a mixed method design: secondary analysis of the HIV Cost and Services Utilization Study (HCSUS) and content analysis of the Participating and Communicating Together Study (PACT). This information can be used to strengthen medication adherence interventions for HIV positive drug using populations. Moreover, because drug-related HIV/AIDS disproportionately affects African Americans and other communities of color, research that leads to improvements in HIV treatment outcomes for drug-using populations may also help reduce racial/ethnic health disparities.